Addressing the Important Role of Genetic Testing in Prostate Cancer

As researchers learn more about prostate cancer and the important role that genetic testing can play for patients and their families, the focus now needs to be on determining the best way to put this testing into practice, says Wassim Abida, MD, PhD.

Abida, assistant attending oncologist, Memorial Sloan Kettering Cancer Center, discussed the current role of genetic testing in prostate cancer, how genetic testing can benefit patients and their families, and the challenges that still need to be addressed in this area, during an interview with Targeted Oncology.

TARGETED ONCOLOGY: Can you discuss the current role of genetic testing in men with prostate cancer?

Abida: This is a little bit new to the field [of prostate cancer]. It’s better established in other diseases like breast and ovarian cancer, but the more we are learning about prostate cancer, and the more we understand that there is an important role for genetic testing, at least for some men, we need to reach a consensus about how to institute that. That’s the role of the 2017 Philadelphia Prostate Cancer Consensus. There is broad representation from across different fields to reach a consensus about who should be tested, what kind of testing should we do, and how do we interpret and act on this testing.

TARGETED ONCOLOGY: Why has genetic testing not been more commonly used in prostate cancer?

Abida: There was not as much recognition that inherited mutations could be identified with as high of a frequency in prostate cancer as was found in other diseases. Now, we’re realizing that a lot of men with prostate cancer, particularly men who develop more aggressive or metastatic prostate cancer that spreads, have an identifiable mutation that is inherited that we can find through genetic testing. These mutations have implications for the patient themselves, in terms of risk of having other kinds of cancer, and for their families, who could inherit that type of mutation and who could be screened differently. Lastly, we’re realizing it can help in terms of treatment of patients who have that mutation, because some of these mutations could potentially predict for response to specific types of drugs.

The main reason we haven’t been doing that for men with prostate cancer is that there was a lack of recognition previously of the frequency of these types of mutations that we knew are more frequent in breast cancer and ovarian cancer, but now we’re realizing are also quite frequent, in about 1 in 9 or 1 in 10 men with metastatic prostate cancer, based on the largest study that we’ve had so far.

TARGETED ONCOLOGY: How can genetic testing be beneficial to patients?

Abida: There is a lack of information on this now, and we’re learning more and more, but realizing now that a significant proportion—1 in 9 or 1 in 10 is a real number that can have a lot of significance. A lot of men really do want to find out about their predisposition for developing this cancer or the chance that a male family member might have an increased risk of developing this disease and how that can affect screening for them. For some types of inherited mutations, female members of the family can be effected too by other diseases, like breast cancer or ovarian cancer. I would say a lot of men with prostate cancer would like to know this for the benefit of family members and for screening, and it would obviously be relevant and actionable for making those kinds of decisions for family members, but also very important in terms of making treatment decisions.

There are new treatments that are coming about. A lot of these treatments are based on changes in DNA, and 1 of those changes in DNA can be inherited. A lot of men, even without relatives who could be affected by it, would like to know if there is something we can act on to improve their treatment, and so it’s relative from the perspective as well. There are 2 reasons why this may affect men with prostate cancer, particularly men with advanced prostate cancer.

TARGETED ONCOLOGY: What are some of the challenges associated with genetic testing that still need to be tackled?

Abida: There are multiple levels. The first one is deciding who should be tested—what are the populations most at risk and who is going to benefit the most from testing, then have honest discussions with patients about the risk versus benefit of testing, as we always do for all kinds of testing and treatments in general.

Secondly, the question is what is our level of knowledge about particular changes in DNA so that we can focus on the ones that are really important and are going to change decision making for patients and their families. You could argue that if you don’t have enough evidence or confidence in the type of inherited mutation, in terms of how it may affect outcomes for patients and their families, it may be best to not focus on that particular type of change until we learn more about it. The question is how broad should we be in the type of testing that we’re doing, or how focused should we be in terms of focusing on the changes that we are confident increase the risk of cancer in the family and really do affect decisions down the road.

Thirdly, because this is all new, there are also some financial considerations about this that we do need this type of testing to be affordable for patients and their families, and, on a broader basis, to have insurance companies cover it. We have to be judicious in the type of testing we’re doing and focus on what’s going to be helpful to patients and their families.

TARGETED ONCOLOGY: Are there any ongoing trials in this space that you are particularly excited to see the results of?

Abida: From a treatment perspective, there’s a lot of interest in new types of treatments that are focused on men who have both inherited and non-inherited changes in their DNA that affect DNA repair, so there are new treatments that are still investigational at this point that have shown very promising results whereby a man that is found to have a change in inherited or non-inherited types of genes may benefit from that type of treatment. Those trials are ongoing. They started recently and we’re all excited to see the results of those types of trials. This is a treatment implication for doing this kind of inherited testing that would be very relevant.